• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국정보통신학회 2018년도 추계학술대회
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• pp.565-567
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• 2018

The rover acquires its own position information using satellites signals provided by several satellites(at least four or more). For the present, GNSS systems are widely used in various fields. However, there are many factors that cause accuracy errors in positioning between rovers and GNSS satellites. Due to satellite time error, orbit error, ionospheric & convective refraction, multipath, etc., rover can't acquire precise position. Differential GPS(DGPS) and Real-Time Kinematic(RTK) have been developed as compensation techniques to reduce such errors. In this paper, we intend to develop a terminal with RTK technique to acquire precise position information of mobile station.

• Journal of Information Processing Systems
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• 제7권1호
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• pp.53-62
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• 2011

With the steady growth of mobile technology and applications, demand for more storage in mobile devices has also increased. A lightweight block-level protocol, Internet Advanced Technology Attachment (iATA), has been developed to deliver a cost-effective storage network solution for mobile devices to obtain more storage. This paper seeks to contribute to designing and implementing Load Balancing (LB), Network Monitoring (NM) and Write Replication (WR) modules to improve the protocol's scalability and data availability. LB and NM modules are invoked to collect system resources states and current network status at each associate node (server machine). A dynamic weight factor is calculated based on the collected information and sent to a referral server. The referral server is responsible to analyze and allocate the most ideal node with the least weight to serve the client. With this approach, the client can avoid connecting to a heavily loaded node that may cause delays in subsequent in-band I/O operations. Write replication is applied to the remaining nodes through a WR module by utilizing the Unison file synchronization program. A client initially connected to node IP A for write operations will have no hindrances in executing the relevant read operations at node IP B in new connections. In the worst case scenario of a node crashing, data remain recoverable from other functioning nodes. We have conducted several benchmark tests and our results are evaluated and verified in a later section.

• Interaction and multiscale mechanics
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• 제6권2호
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• pp.137-156
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• 2013

In this paper, a meshfree shell adaptive procedure is developed for the applications in the sheet metal forming simulation. The meshfree shell formulation is based on the first-order shear deformable shell theory and utilizes the degenerated continuum and updated Lagrangian approach for the nonlinear analysis. For the sheet metal forming simulation, an h-type adaptivity based on the meshfree background cells is considered and a geometric error indicator is adopted. The enriched nodes in adaptivity are added to the centroids of the adaptive cells and their shape functions are computed using a first-order generalized meshfree (GMF) convex approximation. The GMF convex approximation provides a smooth and non-negative shape function that vanishes at the boundary, thus the enriched nodes have no influence outside the adapted cells and only the shape functions within the adaptive cells need to be re-computed. Based on this concept, a multi-level refinement procedure is developed which does not require the constraint equations to enforce the compatibility. With this approach the adaptive solution maintains the order of meshfree approximation with least computational cost. Two numerical examples are presented to demonstrate the performance of the proposed method in the adaptive shell analysis.

• Smart Structures and Systems
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• 제22권4호
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• pp.399-411
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• 2018

The difficulty in modeling complex nonlinear structures lies in the presence of significant sources of uncertainties mainly attributed to sudden changes in the structure's behavior caused by regular aging factors or extreme events. Quantifying these uncertainties and accurately representing them within the complex mathematical framework of Structural Health Monitoring (SHM) are significantly essential for system identification and damage detection purposes. This study highlights the importance of uncertainty quantification in SHM frameworks, and presents a comparative analysis between intrusive and non-intrusive techniques in quantifying uncertainties for SHM purposes through two different variations of the Kalman Filter (KF) method, the Ensemble Kalman filter (EnKF) and the Polynomial Chaos Kalman Filter (PCKF). The comparative analysis is based on a numerical example that consists of a four degrees-of-freedom (DOF) system, comprising Bouc-Wen hysteretic behavior and subjected to El-Centro earthquake excitation. The comparison is based on the ability of each technique to quantify the different sources of uncertainty for SHM purposes and to accurately approximate the system state and parameters when compared to the true state with the least computational burden. While the results show that both filters are able to locate the damage in space and time and to accurately estimate the system responses and unknown parameters, the computational cost of PCKF is shown to be less than that of EnKF for a similar level of numerical accuracy.

• Journal of Aquaculture
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• 제18권2호
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• pp.92-97
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• 2005

This study examined the partial replacement of the fish meal with meat meal in practical diets for juvenile rock-fish. Five isonitrogenous (48% CP) diets were prepared to contain meat meal at 0% (control), 10%, 20%, 30% and 40% with substituting the mackerel meal in the control diet. Three replicate groups of fish (initial average weight, 4.1g) were hand-fed to visual satiety two times daily for 8 weeks. Survival (>93%) and daily feed intake were not significantly different (P>0.05) among treatments. The best weight gain, feed efficiency and protein efficiency ratio were obtained from fish fed the diets containing 0% and 10% meat meal, and were not significantly different (P>0.05) to those of fish 134 diet containing 20% meat meal. Condition factor, visceralsomatic index and hepatosomatic index were not influenced by dietary meat meal levels. The contents of crude protein and ash of whole body were not significantly affected (P>0.05) by dietary meat meal levels, whereas crude lipid content of fish fed the diets containing 30% and 40% was lower than that of fish fed the control diet. Proximate composition of liver was not influenced by dietary meat meal level (P>0.05). The data obtained in this study indicate that a diet containing $10{\sim}20%$ meat meal could be used for least-cost formulation in juvenile rockfish diet.

• Journal of the Korean housing association
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• 제23권4호
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• pp.49-57
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• 2012

This study was conducted to apply the modular construction method to Han-ok. The modular method, which is differentiated from the existing one, means a construction method that equipments, windows and interior materials are prefabricated as a six-sided object at a plant and then they are assembled at the least process on the spot. As for the theoretical observation, the theoretical basis to apply the modular method to the modular housing and Hanok was divided into environmental and economic aspect. In order to apply the modular method to Hanok, the unit scale and size were selected and the plane of unit module Hanok was developed. And a standard with regard to the unit combination and material lifting transportation method was set and planned. In addition, through the comparison the unit modular Hanok to the existing Hanok, the difference was analyzed and the strength was identified in terms fo design method, structure, construction method, period and cost. In final, the conclusion, with regard to the economic, technical application in future, was drawn through arranging the study contents. The unit modular Hanok to carry out the high-quality dwelling through construction period reduction, standardized construction materials and improved insulation performance can meet the demands for a paradigm of new construction technology.

• Journal of Communications and Networks
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• 제14권1호
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• pp.91-103
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• 2012

Network mobility (NEMO) based on mobile IP version 6 has been proposed for networks that move as a whole. Route optimization is one of the most important topics in the field of NEMO. The current NEMO basic support protocol defines only the basic working mode for NEMO, and the route optimization problem is not mentioned. Some optimization schemes have been proposed in recent years, but they have limitations. A new NEMO route optimization scheme-involving a combination of the optimized route cache protocol (ORC) and reverse routing header (RRH) and the use of a quota mechanism for optimized sessions (OwR)-is proposed. This scheme focuses on balanced performance in different aspects. It combines the ORC and RRH schemes, and some improvements are made in the session selection mechanism to avoid blindness during route optimization. Simulation results for OwR show great similarity with those for ORC and RRH. Generally speaking, the OwR's performance is at least as good as that of the RRH, and besides, the OwR scheme is capable of setting up optimal routing for a certain number of sessions, so the performance can be improved and the cost of optimal routing in nested NEMO can be decreased.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2005년도 춘계종합학술대회
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• pp.843-847
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• 2005

The development of distributed application in the standardized CORBA(Common Object Request Broker Architecture) environments reduces the developing time and maintaining cost of the systems. Because of these advantages, the development of application is being progressed in the several fields using the CORBA environments. The programmers in the CORBA environments usually develop the application programs using the CORBA IDL(Interface Definition Language). The IDL files are compiled by IDL compiler and translated into the stubs and skeleton codes which are mapped onto particular target language. The stubs produced by IDL compilers processes the marshaling a data into message buffer. Before a stub can marshal a data into its message buffer, the stub must ensure that the buffer has at least enough free space to contain the encoded representation of the data. But, the stubs produced by typical IDL compilers check the amount of free buffer space before every atomic data is marshaled, and if necessary, expand the message buffer. These repeated tests are wasteful and incidence of overheads, especially if the marshal buffer space must be continually expanded. Thus, the performance of the application program may be poor. In this paper, we suggest the way that the stub code is maintain the enough free space before marshaling the data into message buffer. This methods were analyzes the overall storage requirements of every message that will be exchanged between client and server. For these analysis, in the Front End of compiler has maintain the information that the storage requirements and alignment constraints for data types. Thus, stub code is optimized and the performance of application program is increased.

• Journal of Information Technology Services
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• 제15권4호
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• pp.125-151
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• 2016

In recent years, O2O (Online to Offline) services get a lot of attention to improve the trust in online shopping and minimize the inconvenience and the cost burden in offline shopping as the number of consumers, who do not show concern about the purchase platform like online or offline, increases. Even though the services have been getting the spotlight as a strong business platform for next generation commerce, there have been only a few studies on the O2O services. The purpose of this research is to investigate the factors which affect the consumer's intention to use location-based O2O services. The study is based on VAM (Value-based Adoption Model) which is able to analyze those factors from the aspects of benefit and sacrifice. We used the partial least squares (PLS) method for empirical analysis, and the result shows that contextual offers, instant connectivity, webrooming and economic efficiency, which fall under the benefit, affect perceived value positively while annoyance and face consciousness, which fall under the sacrifice, do not affect perceived value significantly. In addition, contextual offers and instant connectivity affect trust positively. Location accuracy, which falls under the benefit of location-based O2O service, do not significantly affect perceived value and trust while security risk affects trust and use intention negatively. It appears that trust affects perceived value and use intention positively.

• IE interfaces
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• 제20권2호
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• pp.186-194
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• 2007

Recent deregulation of Korean electricity industry has made each power generation company pay more attention to maximizing its own profit instead of minimizing the overall system operation cost while guaranteeing system security. Electricity power generation problem is typically defined as the problem of determining both the on and off status and the power generation level of each generator under the given fuel constraints, which has been known as Profit-Based Unit Commitment (PBUC) problem. To solve the PBUC problem, the previous research mostly focused on devising Lagrangian Relaxation (LR) based heuristic algorithms due to the complexity of the problem and the nonlinearity of constraints and objectives. However, these heuristic approaches have been reported as less practical in real world applications since the computational run time is usually quite high and it may take a while to implement the devised heuristic algorithms as software applications. Especially when considering long-term planning problem which spans at least one year, the complexity becomes higher. Therefore, this paper proposes an explicit column generation algorithm using power generation patterns and the proposed algorithm is successfully applied to a Korean power generation company. The proposed scheme has a robust structure so that it is expected to extend general PBUC problems.