• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.680-690
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• 2020

In ocean environment, the sound speed gradient of seawater has an important influence on far field sound propagation. The FEM/BEM is used to decouple the vibroacoustic radiation of the spherical shell, and the Green function of the virtual source chain is adopted for decoupling. For far field radiated Sound Pressure Level (SPL), the Beam Displacement Ray normal Mode (BDRM) is employed. The vibration and near-/far-field radiated SPL of spherical shell is analyzed in shallow sea uniform layer, negative/positive gradient, negative thermocline environment, and deep-sea sound channel. Results show that the vibroacoustic radiation of spherical shell acted at 300Hz can be analogous to dipole. When the radiated field of the spherical shell is dominated by large-grazing-angle waves, it can be analogous to vertically distributed dipole, and the far field radiated SPL is lower; while similar to horizontally distributed dipole if dominated by small-grazing-angle waves, and the far field SPL is high.

• ETRI Journal
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• v.44 no.2
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• pp.313-326
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• 2022

This study presents a noble scheme for distributed and parallel simulations with optimized agent placement for simulation instances. The traditional parallel simulation has some limitations in that it does not provide sufficient performance even though using multiple resources. The main reason for this discrepancy is that supporting parallelism inevitably requires additional costs in addition to the base simulation cost. We present a comprehensive study of parallel simulation architectures, execution flows, and characteristics. Then, we identify critical challenges for optimizing large simulations for parallel instances. Based on our cost-benefit analysis, we propose a novel approach to overcome the performance constraints of agent-based parallel simulations. We also propose a solution for eliminating the synchronizing cost among local instances. Our method ensures balanced performance through optimal deployment of agents to local instances and an adaptive agent placement scheme according to the simulation load. Additionally, our empirical evaluation reveals that the proposed model achieves better performance than conventional methods under several conditions.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.5
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• pp.46-56
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• 2013

This research prepared safety standard for out-door fitness and this research's purpose is to evaluate and investigate safety condition for out-door fitness which was distributed in domestic residence by applying TUV standard which evaluate product's safety inspection. We choose twelve companies which have many sales' amount and investigated for ten out-door fitness which have high consumer preferences. As a result of that, the ratio of successful applicants for safety evaluation was 55.1%. The terms desired was evaluated highly in safety for out-door fitness's fixing condition. However, the terms desired was evaluated lowly in safety for movable condition. Fitness equipment which has high consumer preferences was compared lowly than other equipment in safety part. It was analyzed that there was no difference in safety evaluation according to manufacturing company. So, it is necessary to prepare safety standard by establishing law in order to prevent accident while they are using because we cannot think that fitness equipments which was distributed in domestic area have high safety. We think that preparing safety standard can influence on preventing accident and reinforcing out-door fitness manufacturing companies' competitive.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.1
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• pp.53-68
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• 2021

The study aims to propose a locating method of green space for reducing Particulate Matter (PM) in ambient air in conjunction with its source traces and vulnerable groups. In order to carry out the aims and purposes, a literature review was conducted to derive indicators of vulnerable area to PM. Based on the developed indicators, the vulnerable areas and green spaces creation strategies for each cluster were developed for the case of Seongdong-gu, Seoul. As a result, six indicators for vulnerability analysis were came out including the vulnerable groups (children's facilities, old people's facilities), emission sources (air pollutant emission workplaces, roads), and environmental indicators (particulate matter concentration, NDVI). According to the six selected indicators, the target area was divided into 39 hexagons and analyzed to result the most vulnerable areas to particulate matter. As a result of comprehensive vulnerability analysis, the Seongsu-dong area was found to be the most vulnerable to particulate matter, and 5 clusters were derived through k-means cluster analysis. Cluster 1 was analyzed as areas that most vulnerable to particulate matter as a result of the comprehensive analysis, therefore urgent need to create green spaces to reduce particulate matter. Cluster 2 was areas that mostly belonged to the Han River. Cluster 3 corresponds to the largest number of hexagons, and since many vulnerable groups are distributed, it was analyzed as a cluster that required the creation of a green spaces to reduce particulate matter, focusing on facilities for vulnerable groups. Three hexagons are included in cluster 4, and the cluster has many roads and lacks vegetation in common. Cluster 5 has a lot of green spaces and is generally distributed with fewer vulnerable groups and emission sources; however, it has a high level of particulate matter concentration. In a situation where various green spaces creation projects for reducing particulate are being implemented, it is necessary to consider the vulnerable groups and emission sources and to present green space creation strategies for each space characteristic in order to increase the effectiveness of such projects. Therefore, this study is regarded as meaningful in suggesting a method for selecting a green area for reducing PM.

• Journal of Korean Society of Rural Planning
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• v.29 no.1
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• pp.69-79
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• 2023

Uiseong-gun, Gyeongsangbuk-do, one of the representative small rain regions, has developed a traditional irrigation farming system while overcoming and adapting to unfavorable agricultural environments from the days of the ancient nation of Jomunguk to the present. In 2018, its value was recognized and designated as Nationally Important Agricultural Heritage System No. 10. This study was conducted with the purpose of examining the characteristics of the traditional irrigation farming system in Uiseong from the viewpoints of irrigation facilities, irrigation communities, and agricultural activities. The research results are as follows. Uiseong-gun has been expanding irrigation facilities for agriculture since long ago, and it has been investigated that a total of 6,227 irrigation facilities are currently distributed along the Wicheon water system that crosses Uiseong-gun from east to west. Irrigation facilities appear differently depending on the topography. The irrigation facility has a 'su-tong' as an irrigation passage and a corkscrew structure 'mot-tchong' as a water quantity control device, so the amount of water was adjusted as needed. Through this facility, surface water with warmer temperature is supplied to the farmland to prevent cold damage to crops. Uiseong has developed activities to organize irrigation communities in one village or several villages to secure agricultural water from an early age. Currently, this tradition continues, and a total of 213 irrigation communities manage 375 irrigation facilities (6.0% of all irrigation facilities). Through this organization, called Mong-ri-gye, water for agriculture is obtained, managed, and distributed equitably. In order to increase agricultural production, Uiseong implemented double cropping by converting rice fields and fields. In the case of Mt. Geumseong, double cropping of rice and barley was mainly carried out until the 1970s, but since the 1980s, double cropping of rice and garlic has been implemented with higher income. One of the unique features of the agricultural system of this region is the spectacular landscape that changes simultaneously from field to rice field in spring and from rice field to field in autumn.

• Journal of the Korean Society for information Management
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• v.19 no.2
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• pp.69-92
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• 2002

A hybrid information service may include local and/or remote distributed services, both and electronic. Also, a hybrid information service can be described as one which an appropriate range of heterogeneous information services is presented to the user in a consistent and integrated way via a single interface. The purpose of this study is to suggest high-level requirements and logical architecture to design hybrid library. High-level requirements analysis for hybrid library need to contain baseline requirements, basic system requirements, searching, location, requesting, delivery and payment. A logical architecture need to consider logical architecture for hybrid library management system including user access points, hybrid library management system and hybrid library components and 5 layered architecture including presenter, coordinator, mediator, communicator and provider to achieve local simplicity while still supporting complex functionality of hybrid library.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.3
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• pp.1-6
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• 2008

Data grid shares distributed large data via wide-band network. Such grid environment consumes much time for large data transmission. Because it is implemented on internet as physical network. Many replication strategies were proposed for solving this problem, but they are not optimal in real Data grid environments. Because they were proposed that based on logical topology without consideration of real internet architecture. Grid data access time is largely influenced by internet architecture as physical network of Data grid. In this paper, we propose a new data replication strategy RSIA(Replication Strategy based on Internet Architecture) based on internet architecture. The RSIA places replicas considering structural hierarchy in each element of internet, and avoid the performance bottlenecks to reduce system performance degradation when a data transfer. Through simulation, we show that the proposed RSIA data replication strategy improves the performance of Data Grid environment compared with previous strategies.

• The KIPS Transactions:PartC
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• v.9C no.3
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• pp.323-330
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• 2002

Multicast services are gradually diversified and used widely. Proportionately, they become the center of attackers' attention and there are growing possibilities of an intelligence leak. Therefore, research related to secure multicast should be required to provide multicast service efficiently. This paper presents the architecture for secure multicast which provides efficient group management mechanism in group consists using member's dynamic join and leave. This architecture can provide secure multicast services to many users with regard to security aspects in one-to-many communication. The simulation results show that the proposed architecture achieves an efficient group management and a secure data transmission with low latency compared with the other existing secure multicast architecture.

• The Transactions of the Korea Information Processing Society
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• v.7 no.1
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• pp.12-19
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• 2000

In the development of a production process scheduling system a collaboration method must be defined for the cooperation among submodules within the system. The blackboard architecture is exploited for solving the collaboration problem, which is one of the problem solving architecture that belongs to the distributed artificial intelligence. The dynamic states of the problem solving processes are presented in the hierarchically constructed shared working memory called as a blackboard. The communication for the collaboration is done through the blackboard. The problem solving steps are contained in the global controller, one of a component that consists the blackboard architecture, as knowledge. The global controller activates proper submodules based on the knowledge. By applying the blackboard architecture the collaboration problem among submodules in the grating production process scheduling system (GPSS) has been solved as well as the system became adaptable to the future modifications and expansions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.1
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• pp.58-70
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• 1990

This paper describes a VLSI implementation of real-time two dimensional DCT processor for the subprimary rate video codec system. The proposed architecture exploits the parallelism and concurrency of the distributes architecture for vector inner product operation of DCT and meets the CCITT performance requirements of video codec for full CSIF 30 frames/sec. It is also shown that this architecture satisfies all the CCITT IDCT accuracy specification by simulating the suggested architecture in bit level. The efficient VLSI disign methodology to design suggested architecture is considered and the module generator oriented design environments are constructed based on SUN 3/150C workstation. Using the constructed design environments. the suggensted architecture have been designed by double metal 2micron CMOS technology. The chip area fo designed 8x8 2-D DA-DCT (Distributed Arithmetic DCT) processor is about 3.9mmx4.8mm.