• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.3D
• /
• pp.259-267
• /
• 2012

The development of construction automation systems is proposed as a potent solution to the difficulties encountered by the construction industry and the preparation for the rapidly changing construction environment. A research concerning an intelligent excavation system has taken place since 2006. The intelligent excavation system has several functions for environment sensing, 3D site modeling, work planning, work path generation, unmaned control, and information management. This paper presents a space information model and a work path simulator for work planning and work path generation which is one of key technologies required to apply the earthwork system to the real world. A data structure for an earthwork site is suggested. It overcomes the limitations of previous data structures such as Quadtree and Octree. The work path simulator can generate an effective work path with considering information on work environment, equipment and operator's heuristic. The work path generated by the simulator is compared with that suggested by human operators.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.44 no.8
• /
• pp.695-701
• /
• 2016

Spacecraft propulsion system is a kind of rocket engine that has been developed from the end of 1950s for attitude control and orbit maintenance of satellite. Since the spacecraft propulsion system has to be used for a relatively long time, therefore, stability of propellant and life of thruster could be very important factor for propulsion system design. Recently, green propellant propulsion and all electrical propulsion system have became very important issue, and we also need a development according to well organized plan. In this paper, we will introduce the development status, key technologies and development prospect of spacecraft propulsion system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.11a
• /
• pp.613-615
• /
• 2009

This paper is to introduce Hanwha Aerospace R&D Center's development status of TVC(Thrust Vector Control) system and control valves for Korean space launch vehicles. With the successful development of KSR-III TVC system, Hanwha have developed TVC system and RCS control valves for KSLV-I. Also, in the advance research area of KSLV-II, Hanwha have participated in LOx and fuel flow control valves and LOx shut-off valve development in the engine supply system. Based on the accumulated experiences and technologies in the aerospace key components and system development, Hanwha will make an important contribution to KSLV-II development in the future.

• Journal of Advanced Navigation Technology
• /
• v.8 no.2
• /
• pp.144-154
• /
• 2004

In this paper we apply the space-time block codes (STBCs), the key technologies for the 4th generation mobile communication systems, to the OFDM system and analyze their performances. First, we derive the signal models for representative STBC schemes and demodulation procedures for each scheme. We also select the parameters for OFDM system considering mobile cellular environments and assign adequate modulation schemes to STBC-OFDM schemes according to the transmission rate from 2bps/Hz to 4bps/Hz. We finally compare and analyze the performances of STBC-OFDM schemes for the selected transmission rates through computer simulations, together with performance comparison when the same modulation scheme being adopted.

• Journal of The Korean Association For Science Education
• /
• v.42 no.2
• /
• pp.177-184
• /
• 2022

This article aims to explain the concept and characteristics of the 'Intelligent Science Lab', which is being promoted nationwide in Korea since 2021. The Korean Ministry of Education creates a master plan containing a vision for science education every five years. The most recently announced '4th Master plan for science education (2020-2024)' emphasizes the policy of setting up an 'intelligent science lab' in all elementary and secondary schools as an online and offline space for scientific inquiry using advanced technologies, such as Internet of Things and Augmented and Virtual Reality. The 'Intelligent Science Lab' project is being pursued in two main directions: (1) developing an online platform named 'Intelligent Science Lab-ON' that supports science inquiry classes, and (2) building a science lab space in schools that encourages active student participation while utilizing the online platform. This article presents the key features of the 'Intelligent Science Lab-ON' and the characteristics of intelligent science lab spaces newly built in schools. Furthermore, it introduces inquiry-based science learning programs developed for intelligent science labs. These programs include scientific inquiry activities in which students generate and collect data ('data generation' type), utilize datasets provided by the online platform ('data utilization' type), or utilize open and public data sources ('open data source' type). The Intelligent Science Lab project is expected to not only encourage students to engage in scientific inquiry that solves individual and social problems based on real data, but also contribute to presenting a model of online and offline linked scientific inquiry lessons required in the post-COVID-19 era.

• The KIPS Transactions:PartD
• /
• v.11D no.2
• /
• pp.443-452
• /
• 2004

The paper presents an intelligent space management system for ubiquitous computing. The system is basically a home/office automation system that could control light, electronic key, and home appliances such as TV and audio. On top of these basic capabilities, there are four elegant features in the system. First, we can access the system using either a cellular Phone or using a browser on the PC connected to the Internet, so that we control the system at any time and any place. Second, to provide more human-oriented interface, we integrate voice recognition functionalities into the system. Third, the system supports not only reactive services but also proactive services, based on the regularities of user behavior. Finally, by exploiting embedded technologies, the system could be run on the hardware that has less-processing power and storage. We have implemented the system on the embedded board consisting of StrongARM CPU with 205MHz, 32MB SDRAM, 16MB NOR-type flash memory, and Relay box. Under these hardware platforms, software components such as embedded Linux, HTK voice recognition tools, GoAhead Web Server, and GPIO driver are cooperated to support user-friendly intelligent space.

• Tunnel and Underground Space
• /
• v.25 no.2
• /
• pp.133-143
• /
• 2015

Gas hydrate is a solid substance composed of natural gas constrained in water molecules under low temperature and high pressure conditions. The existence of hydrates has been reported to be world-widely distributed, mainly at permafrost and deep ocean floor. Test productions of small amount of natural gas from the on-shore permafrost have been accomplished in U.S.A and Canada, but, world-first and the only production case from off-shore hydrate bearing sediments was in Nankai trough, Japan. In this study, we introduce key technologies in gas production from hydrates by analyzing the Japanese off-shore gas production project in Nankai trough in terms of depressurization- induced dissociation so as to utilize planned domestic gas production test in Ulleung basin.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.10
• /
• pp.4136-4156
• /
• 2020

Recently, data can be safely shared or stored using the infrastructure of cloud computing in various fields. However, issues such as data security and privacy affect cloud environments. Thus, a variety of security technologies are required, one of them is security technology using CP-ABE. Research into the CP-ABE scheme is currently ongoing, but the existing CP-ABE schemes can pose security threats and are inefficient. In terms of security, the CP-ABE approach should be secure against user collusion attacks and masquerade attacks. In addition, in a dynamic cloud environment where users are frequently added or removed, they must eliminate user access when they leave, and so users will not be able to access the cloud after removal. A user who has left should not be able to access the cloud with the existing attributes, secret key that had been granted. In addition, the existing CP-ABE scheme increases the size of the ciphertext according to the number of attributes specified by the data owner. This leads to inefficient use of cloud storage space and increases the amount of operations carried out by the user, which becomes excessive when the number of attributes is large. In this paper, CP-ABE access control is proposed to block access of withdrawn users in dynamic cloud environments. This proposed scheme focuses on the revocation of the attributes of the withdrawn users and the output of a ciphertext of a constant-size, and improves the efficiency of the user decryption operation through outsourcing.

• The Journal of the Korea Contents Association
• /
• v.15 no.3
• /
• pp.32-39
• /
• 2015

In this paper, We propose the futuristic map using variety technology of advanced ICT-based. The futuristic maps are expected to developed into a new format of user participation to express the results in various formats through the understanding and interpretation of the facts and phenomena of tangible and intangible that exist in the real world. In the future, the map is expected to be developed into form of a new paradigm map made in real time that economy, industry, the collection of information necessary for everyday life, processing, usage, analysis, distribution and sharing. In this paper, we provide a real-time personalized contents to digitize the information of the real space based on the concept of map, databases, spatial analysis and describes the key technologies that characterized by the representation of time-series data by analyzing and prediction every field macro phenomena of society, economy, culture and etc. And we establish the concepts of the 'New Paradigm Map' for future creative economy.

• KIPS Transactions on Software and Data Engineering
• /
• v.10 no.8
• /
• pp.331-338
• /
• 2021

Metaverse is a compound word of 'meta' and 'universe', which means transcendence and the world. It is a digital world where daily life and economic activities are possible. While the Metaverse is being actively used as an alternative space to enjoy leisure life since COVID-19, not much academic research on Metaverse in Korea has been done yet. Based on the previous research on Metaverse in Korea and overseas we conducted a typology analysis on cultural leisure-based Metaverse and a study on its key features. Considering the current situation in which the Metaverse era is blooming we also investigated the development trends of the Metaverse and related technologies at home and abroad. We also presented the direction of advancement of the cultural leisure-based Metaverse. This study differentiates itself from previous domestic and foreign studies by discovering and analyzing theoretical models, frameworks and features in terms of society, collaboration, and leisure use through case studies. It is meaningful that this research presents directions on further Metaverse research that reflect the current information technology (IT) and changes in life.