• Geophysics and Geophysical Exploration
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• v.9 no.3
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• pp.193-206
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• 2006

Among various borehole seismic testing techniques for determining body wave velocity, crosshole seismic method has been known as one of the most suitable technique for evaluating reliably geotechnical dynamic properties. In this study, to perform successfully the crosshole seismic test for rock as well as soil layers regardless of the groundwater level, multi-purposed spring-loaded source which impact horizontally a subsurface ground in vertical borehole was developed and applied at major facility sites in Korea. The geotechnical dynamic properties were evaluated by determining efficiently the body wave velocities such as shear wave velocity and compressional wave velocity from the horizontally impacted crosshole seismic tests at study sites, and were provided as the fundamental parameters for the seismic performance evaluation and seismic design of the target facilities.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12C
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• pp.1181-1185
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• 2005

A combining of MIMO signal processing with OFDM is regarded as a promising solution of enhancing the performance of next generation wireless system. Therefore, in this paper, an OFDM-based wireless system employing layered space-time architecture is considered for a high-rate transmission. In the MIMO-OFDM system, we evaluate the PAR performance using the SLM approaches. The investigated SLM scheme for MIMO-OFDM signals selects the transmitted sequence with lowest average PAR over all transmitting antennas and retrieves the side information very accurately at the expense of a slight degradation of the PAR performance. The low probability of false side information can improve the overall detection performance of the MIMO-OFDM system with erroneous side information compared to the ordinary SLM approache, respectively. Also, we provide closed form of the average BER performance in MIMO-OFDM system using analytic approach.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.6
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• pp.1214-1221
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• 2007

Ad-hoc network is soft wireless communication network that is consisted of mobile node and clusters without helping of infrastructure. We propose a new ad hoc multicast routing protocol for based on the ontology scheme called inference network. Ontology knowledge-based is one of the structure of context-aware. Proposed structure is consisted of context awareness parameters as like distance between each nodes. The proposed architecture performs two types of routing discovery. One is Flooding Discovery Routing(FDR) for comparing analysis step and Local Discovery Routing(LDR) to compose path of node forecast(preservation) step from node's state value. The inference network structure of proposed RODMRP(Resilient Ontology-based Dynamic Multicast Routing Protocol) adopts a tree structure to enhance an efficient packet in various environment between mobile node. We will have developed an algorithm that will desist multi-hierarchy Layered networks to simulate a desired system.

• Journal of the Korea Society for Simulation
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• v.25 no.4
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• pp.43-52
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• 2016

Wireless sensor network (WSN) technology has been implemented using commercial off-the-shelf microcontrollers (MCUs), In this paper, we propose a simulation environment to realize the physical evaluation of FPGA-based node by considering vertically cross-layered WSN in terms of physical node device and network interconnection perspective. The proposed simulation framework emulates the physical FPGA-based sensor nodes to interoperate with the NS3 through the runtime infrastructure (RTI). For the emulation and interoperation of FPGA-based nodes, we extend a vendor-providing FPGA design tool from the host computer and a script to execute the interoperation procedures. The standalone NS-3 is also revised to perform interoperation through the RTI. To resolve the different time-advance mechanisms between the FPGA emulation and event-driven NS3 simulation, the pre-simulation technique is applied to the proposed environment. The proposed environment is applied to IEEE 802.15.4-based low-rate, wireless personal area network communication.

• Journal of Convergence for Information Technology
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• v.11 no.11
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• pp.335-344
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• 2021

The purpose of this paper is the development of course data models and learning achievement computation algorithms for enabling the course-embedded assessment(CEA), which is essential of competency-based education in higher education. The previous works related CEA have weakness in the development of the systematic solution for CEA computation. In this paper, we propose data models and algorithms to implement competency-based assessment system. Our data models are composed of a layered architecture of learning outcomes, learning modules and activities, and an associative matrix of learning outcomes and activities. The proposed methods can be applied to the development of the course-embedded assessment system as core modules. We evaluated the effectiveness of our proposed models through applying the models to a practical course, Java Programing. From the result of the experiments we found that our models can be used in the assessment system as a core module.

• Journal of Convergence for Information Technology
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• v.9 no.8
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• pp.45-52
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• 2019

This paper proposes the design of a closed-loop stepping motor drive for real-time Ethernet (RTE), which can be easily applied to a variety of RTE protocols. The proposed design is divided into a closed-loop step motor drive which can be reused for various types of RTE protocol and RTE module developed for each specific RTE protocol. It is based on a layered architecture so that the motion control algorithm can be easily reused independently of the RTE protocol and motion profile. To verify the proposed design, closed-loop motor drives based on EtherCAT and Mechatrolink III were developed and their performances were evaluated. Cycle time was measured to verify the real-time communication performance of the developed EtherCAT and Mechatrolink III based motor drive. As a result, the EtherCAT was 7.5 times faster than the Mechatrolink III when 32 motor drives were connected.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.3
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• pp.83-95
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• 2022

This study aims to present primary data for habitat restoration and artificial breeding conditions of L. unmunsana by identifying the habitat conditions and the larvae's food sources. In order to investigate the habitat characteristics of the adult L. unmunsana and land snails, which are the primary food sources for the larvae, field surveys were conducted on a total of 10 habitats in south-central parts of Korea including Sanseongcheon, Jeonju. The results revealed that the L. unmunsana habitat in the Sanseongcheon area had a broadleaf forest with a multi-layered vegetation structure, adjacent water features, and the north/northeast/northwest slopes with little effect of artificial lighting. The adult L. unmunsana in the Sanseongcheon area appeared from the end of May to the end of June, and was especially intensively observed around the middle of June. The most active time was from 23:30 to 00:30 with a temperature range of 19~22℃ and higher than 80% humidity. The peak count of the observed adults L. unmunsana was a total of 774 on June 11, 2021. In the case of land snails, 11 families and 23 species were observed in 10 habitats of L. unmunsana, and Euphaedusa fusaniana was the most extensive and the most observed in the five survey areas. The land snails of L. unmunsana habitats are mostly found under the organic layers of leaves and a fallen tree branch in broadleaf forests, where a thick organic material layer buffers temperature changes and provides high humidity for various snails. These habitat conditions are suitable for the larva of L. unmunsana and land snails to inhabit, feed, hide and hibernate.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.8
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• pp.1205-1212
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• 2022

Cyber threat targeting ICS (Industrial Control System) has indicated drastic increases over the past decade and Cyber Incident in Critical Infrastructure such as Energy, Gas Terminal and Petrochemical industries can lead to disaster-level accidents including casualties and large-scale fires. In order to effectively respond to cyber attacks targeting ICS, a multi-layered defense-in-depth strategy considering Control System Architecture is necessary. In particular, the centralized security log system integrating OT (Operational Technology) and IT (Information Technology) plays an important role in the ICS incident response plan. The paper suggests the way of implementing centralized security log system that collects security events and logs using OPC Protocol from Level 0 to Level 5 based on IEC62443 Purdue Model to integrate ICS security logs with SIEM (Security Information Event Management) operated in IT environment.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.40 no.4
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• pp.15-31
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• 2022

This study interpreted the logical validity of the landscape restoration and maintenance patterns of Changgyeonggung Palace, where modern landscapes coexist. The results of the study are as follows; First, the changes in the landscape restoration and maintenance attitude concerning the Changgyeonggung management organization were identified. With the establishment of the Office of the Imperial Garden, an imperial property was nationalized. The Cultural Heritage Managing Department was opened in 1961, and Changgyeonggung Palace were preserved as designated as historical sites in 1963. An environmental purification was implemented by the Changgyeonggung Office as a follow-up measure for restoration in 1983. As the Cultural Heritage Administration promoted in 1999 and the Royal Palaces and Tombs Center was established in 2019, the palace has been managed professionally as a palace landscape to provide a viewing environment. Second, In the 'Purification Period of Changgyeongwon(1954~1977)', environmental purification was carried out to restore amusement facilities, install facilities for cherry blossom viewing, and develop the place into a national zoo. In the 'Reconstruction Period of Changgyeonggung(1983~1986)', restoring function as an urban park, reserving green areas, the outside space was recreated in the traditional feel, and the forest area was generally maintained. In the 'Supplementation Period of Traditional Landscape Architecture Space(1987~2009)', a uniform green landscape was created with pine trees and various vegetation landscapes centered on the flower beds. In the 'Improvement and Maintenance Period of Viewing Environment(2010~2022), a master plan was reestablished on the premise of utilization, but maintenance has been carried out in a small scale centering on unit space. Third, regarding the validity of the landscape restoration and maintenance, It was found in terms of 'originality' that the recovery of the palace system has not been expanded for over 40 years in existing areas. The 'characteristics of the times', which shows whether multi-layered history was taken into account, Changgyeongwon was excluded from the discussion in the process of setting the base year twice. In terms of 'integrity,' the area of the Grand Greenhouse where the historic states coexists needs a maintenance policy that binds the greenhouse, carpet flower bed, and Chundangji Pond. The 'utility' identified as the utilization of spaces suggests the establishment of a sense of place in the Grand Greenhouse area, which is concentrated with programs different from other areas.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.4
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• pp.56-75
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• 2023

As of 2019, for the 'Island I Want to Visit' project, Banwol and Bakji Islands, located in Shinan-gun, started color marketing to create a tourist attraction by painting roofs, buildings, and facilities purple. As this landscape change was evaluated as a 'dangerous but beautiful attempt,' it was recognized as the 'World's Best Tourism Village' in 2021, drawing attention from domestic and foreign tourists. However, the residents of the islands, who created and enjoy the benefits of the landscape, were alienated from the planning stage. This study investigated the meanings and symbols of residents' perceptions of the purple landscape. The cultural landscape frame of new cultural geography, which interprets the landscape's symbolic meaning and ideological signs, was utilized. In addition, a holistic approach was applied to understand the residents' perceptions of the multi-layered environment. Therefore, the perception of purple, the main color of the islands, the overall landscape and individual places, and the general perception of the Purple Island project were investigated. After the Purple Islands Project, the main senses for recognizing the villages focused on sight, and the residents were satisfied with the purple landscape as it improved the underdeveloped village environment. This satisfaction was based on lessening the negative memories experienced as an island rather than a value judgment on the purple color. In addition, the perception of the symbolic landscape, which has a social and universal system, has been subdivided and reorganized, including for tourism functions. It can be understood as an aspect of the spectacle landscape that appears in cosmopolitanism. However, in the process of transforming into a tourist attraction, it was discovered that the residents recognize the value of local resources and create a new cultural landscape. In addition, the perception of the relationship between Banwol and Bakji has also changed around tourism.