• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1221-1226
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• 2004

While the environment of usage of information and technology is getting stable and technology is being developed more deeply due to the globalization, making information, standardization, in order to make a fast response to the new industry strategy and business environment, mutual communication and management of correct and fast information are focused on as fundamental elements of keeping competitive power. Accordingly strategic development of urban transit operation organization, storage of information technology of urban railroad, and buildup of standard information infra are very important, so that computerized information system has been built up standardizing efficient maintenance framework of urban transit facilities. To maintain these facilities efficiently, storing the real-time information by standardizing the maintenance organization and building up computerized information system are very important with management of information history of existing maintenance work. Therefore, for the efficient maintenance of station facilities among urban transit facilities, standardized facilities classification and definition of management elements, and the plan of designing and building standardized database about station facilities through standardizing technology resources are described in, this paper.

• Journal of Ocean Engineering and Technology
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• v.32 no.6
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• pp.411-418
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• 2018

This paper introduces a new method of ice load generation in the time domain for the station-keeping performance evaluation of Arctic offshore structures. This method is based on the ice load spectrum and mean ice load. Recently, there has been increasing interest in Arctic offshore technology for the exploration and exploitation of the Arctic region because of the better accessibility to the Arctic ocean provided by the global warming effect. It is essential to consider the ice load during the development of an Arctic offshore structure. In particular, when designing a station-keeping system for an Arctic offshore structure, a consideration of the ice load acting on the vessel in the time domain is essential to ensure its safety and security. Several methods have been developed to consider the ice load in the time domain. However, most of the developed methods are computationally heavy because they consider every ice floe in the sea ice field to calculate the ice load acting on the vessel. In this study, a new approach to generate the ice load in the time domain with computational efficiency was suggested, and its feasibility was examined. The ice load spectrum and mean ice load were acquired from a numerical analysis with GPU-event mechanics (GEM) software, and the ice load with the varying heading of a vessel was reconstructed to show the feasibility of the proposed method.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.208-222
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• 2021

Managing with the presence of sea ice is the primary challenge in the operation of floating platforms in the Arctic region. It is widely accepted that offshore structures operating in Arctic conditions need station-keeping methods as well as ice management by icebreakers. Dynamic Positioning (DP) is one of the station-keeping methods that can provide mobility and flexibility in marine operations. The presence of sea ice generates complex external forces and moments acting on the vessel, which need to be counteracted by the DP system. In this paper, an icevaning control algorithm is proposed that enables Arctic offshore vessels to perform DP operations. The proposed icevaning control enables each vessel to be oriented toward the direction of the mean environmental force induced by ice drifting so as to improve the operational safety and reduce the overall thruster power consumption by having minimum external disturbances naturally. A mathematical model of an Arctic offshore vessel is summarized for the development of the new icevaning control algorithm. To determine the icevaning action of the Arctic offshore vessel without any measurements and estimation of ice conditions including ice drift, task and null space are defined in the vessel model, and the control law is formulated in the task space. A backstepping technique is utilized to handle the nonlinearity of the Arctic offshore vessel's dynamic model, and the Lyapunov stability theory is applied to guarantee the stability of the proposed icevaning control algorithm. Experiments are conducted in the ice tank of the Korea Research Institute of Ships and Ocean Engineering to demonstrate the feasibility of the proposed approach.

• Journal of Bio-Environment Control
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• v.16 no.3
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• pp.167-173
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• 2007

This study was conducted to improve light environment of oriental melon cultivation in winter season. Three polyolefin foreign films (J-1, J-2, J-3) and three polyethylene domestic films (K-1, K-2, K-3) with different film thickness, ultraviolet ray interception and infrared ray absorption were used. As the result of this experiment, soluble solid of oriental melon fruit in K-3 was $14.3^{\circ}Brix$, those in J-3 and J-2 were higher by 1.3 and $0.8^{\circ}Brix$, respectively. Chromaticity (a value) of pericarp in K-3 was 0.5, those in J-3, J-1 and J-2 were higher by 3.3, 2.3 and 1.9, respectively. Especially, fermented and malformed fruit rates in J-1, J-2 and J-3 were decreased and marketable fruit rates were increased. Marketable yield in K-3 was 1,622 kg per 10a, those in J-1, J-3 and J-2 were increased by 31.2%, 23.8% and 18.5% compare to K-3, respectively. In this study, Polyolefin films (J-1, J-2, J-3) with thickness and infrared ray absorption ratio keeping higher heat conservation, therefore, soluble solid and chromaticity of fruit were increased, fermented fruit rate was decreased, and marketable fruit rate and yield were increased.

• IE interfaces
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• v.23 no.2
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• pp.108-117
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• 2010

Wireless sensor network may be installed where it is hard to access or where one has to constantly gather data without any human's monitoring. Sensors which compose a sensor network are usually small with poor battery capacities and thus energy-efficient usage is very important because of difficulties in replacing or recharging the batteries to make the lifetime of the whole sensor network longer. LEACH protocol, a well-known hierarchical routing protocol, may resolve this problem by distributing the role of cluster header evenly to the sensor nodes in the whole area of network at each round. In this thesis, we introduce a variant of LEACH protocol which considers the distance between base station and sensors in the way that if a node is far from the base station then the probability that this node becomes a cluster header is low. Experiments to evaluate the energy efficiency and the ability to collect the information show that the proposed method in this paper has maintained much wider sensing area while keeping the energy efficiency same as LEACH.

• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.72-77
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• 2007

This study was conducted to investigate the effect of functional cover film on oriental melon fruit quality under unheated plastic greenhouse cultivation in cold period. The 6 kind of films having different characteristics were covered at plastic greenhouses and oriental melon seedlings were cultivated at 2 regions of Seongju, respectively. The air-temperatures in plastic greenhouses of J-1 and J-2, having high infrared absorption rate, were about $2{\sim}5^{\circ}C$ higher than K-3. The contents of ${\beta}-carotene$ and sugar of fruit showed significant difference between functional and normal films. The sucrose, determining a sweetness during maturation, and soluble solids content of fruits cultivated in J-1, J-2, J-3, and K-1 were higher than those of K-2 and K-3. Ascorbic acid of fruits was highest in K-2 having low light transmission rate and thermo-keeping capacity. There was no significant difference in mineral content among all of cover films. These results indicated that the use of functional greenhouse covering films could improve fruit quality such as ${\beta}-carotene$ and sugar content of oriental melon.

• Journal of the Korean Society for information Management
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• v.34 no.4
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• pp.293-320
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• 2017

This study aims to analyze the current status of records management in local broadcasting stations. To that end, it conducted interviews with personnels in charge of keeping records in KBS in J province, MBC in J province, and 2 local commercial broadcasting stations as well as KBS headquarter. The findings show that the local broadcasting stations keep digital files of born-digital broadcast records in a server in a relatively systematic way. However, they never digitalized their analog records and do not even know the exact volume of total records they own. In addition, they have significant difficulties in preserving and utilizing broadcast records because of outdated preservation facilities and information retrieval systems. Based on the findings, this study suggests ways to improve current broadcast record management such as preparation of record management guidelines, construction of an inventory for owned records, digitalization initiative, and provision of metadata education for PDs, etc.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.2
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• pp.139-144
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• 2004

The flight control system designed for an unmanned airship, which is under development by KARI, is in reduced. First, the dynamic characteristics of the airship are addressed, which are fairly different from those of the nominal aircraft. In order to implement autonomous flight for the unmanned airship, flight control logic is designed including autopilot and guidance law. The autopilot is designed under consideration of the velocity region of the unmanned airship. The guidance laws are implemented in main operational modes such as point navigation, station keeping and spiral up/down for emergency return. Their simulation results are also presented in order to validate performances of the flight control system.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1468-1477
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• 2011

Central government and local self-governing bodies are actively promoting bicycle-riding as a solution for transportation, environment, energy and health. They put lot of efforts in the practice of bicycle-related policies such as building bicycle-related infrastructure and creating task force team to improve the bicycle-related systems. However, there is no substantive improvement in the city rail operation agencies regarding the bicycle-related facilities and operation. The expansion of bicycle-related infrastructure in city rail stations is urgently required considering the increase in demands from the bicycle-riders for the facility and bicycle-related service improvement. Accordingly, this study suggests a bicycle-riding vitalization plan linking the city rail and bicycle by providing with a bicycle custody place in the city rail stations which will have comprehensive convenience facilities including the safe-keeping facility for bicycles.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.711-716
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• 2003

This study considers the implementation issues of the inter-vehicle communication system for the vehicle platoon experiments via a testbed. The testbed, which consists of three scale vehicles and one RCS(remote control station), is developed as a tool for functions evaluation between simulation studies and full-sized vehicle researches in the previous study. The cooperative communication of the vehicle-to-vehicle or the vehicle-to-roadside plays a key role for keeping the relative spacing of vehicles small in a vehicle platoon. The static platoon control, where the number of vehicles remains constant, is sufficient for the information to be transmitted in the suitably fixed interval, while the dynamic platoon control such as merge or split requires more flexible network architecture for the dynamical coordination of the communication sequence. In this study, the wireless communication device and the reliable protocol of the flexible network architecture are implemented for our testbed, using the low-cost, ISM band transceiver and the 8-bit microcontroller.