• Journal of the Korean Chemical Society
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• v.51 no.5
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• pp.459-470
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• 2007

The structural equation modeling techniques were used to assess a model of chemistry learning strategy based on self-handicapping tendency and goal orientation. Data were collected during chemistry lessons in two high schools. In the optimal model II-2 of this research, the self-handicapping tendency was negatively related to the use of self-efficacy. The learning goal was positively related to the use of self-efficacy and to learning strategy. The performance- approach goal was positively related to self-efficacy but presented an negative relationship to learning strategy. The performance-avoidance goal was negatively related to self-efficacy but presented an positive relationship to learning strategy. Besides affecting the learning strategy through self-efficacy indirectly, the learning goal, performance-approach goal, and performance-avoidance goal affected learning strategy directly. The self-handicapping tendency and performance- avoidance goal were a negative predictors of self-efficacy, but the learning goal and performance-approach goal were a positive predictors. And the self-efficacy affected learning strategy positively. The implications of these findings for learning strategy in chemistry are discussed. Although the paths model of relationships of the motivations to learn and learning strategies in chemistry education as mentioned above is established, the more systematic search for the higher self-efficacy and learning strategy in different courses and curriculums may be needed.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.2
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• pp.73-86
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• 2018

The increase in the number of private automobiles has incurred various traffic problems. Globally, studies on MaaS(Mobility as a Service) has already been initiated to mobilize the use of public transportation in reducing private passenger cars in roads. This study aims to analyze the passenger's optimal route considering the transfer between different transportation modes through simulation, and analyze the effect of available route through the connected transportation modes. Sejong Special Self-Governing City was chosen as the study area due to its extensive transportation network. As a result of the analysis, the predominant obtainable route is derived either from using public transportation (i.e. bus and subway) only or by bicycle. However, it is also possible to use the car sharing and public bicycle to reach their final destination efficiently when paths that can be traversed were more scrutinized. When various transportation information and location-based services are introduced in smart phone applications, they can provide very useful information to passengers, and also promote social problems such as traffic congestion and environmental issues in the future.

• Journal of KIISE
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• v.42 no.8
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• pp.1057-1064
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• 2015

The tactical network is system based on wireless networking technologies that ties together surveillance reconnaissance systems, precision strike systems and command and control systems. Several alternative paths exist in the network because it is connected as a grid to improve its survivability. In addition, the network topology changes frequently as forces and combatants change their network access points while conducting operations. However, most Internet routing standards have been designed for use in stable backbone networks. Therefore, tactical networks may exhibit a deterioration in performance when these standards are implemented. In this paper, we propose Priority based Multi-Path routing with Local Optimization(PMPLO) for a tactical backbone network. The PMPLO separately manages the global and local metrics. The global metric propagates to other routers through the use of a routing protocol, and it is used for a multi-path configuration that is guaranteed to be loop free. The local metric reflects the link utilization that is used to find an alternate path when congestion occurs, and it is managed internally only within each router. It also produces traffic that has a high priority privilege when choosing the optimal path. Finally, we conducted a simulation to verify that the PMPLO can effectively distribute the user traffic among available routers.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.4
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• pp.217-224
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• 2020

In this study, a framework for optimizing the opening in an outrigger wall is proposed. To solve a constrained bounded optimization problem, an in-house finite element program and SQP algorithm in Python SciPy library are utilized. The openings of the outrigger wall are located according to the strut-tie behavior of the outrigger wall deep beam. A linear interpolation method is used to obtain differentiable continuous functions required for optimization, whereas a database is used for the efficiency of the optimization program. By comparing the result of the two-variable optimization through the moving path of the search algorithm, it is confirmed that the algorithm efficiently determines the optimized result. When the size of each opening is set to individual variables rather than the same width of all openings, the value of the objective function is minimized to obtain better optimization results. It was confirmed that the optimization time can be effectively reduced when using the database in the optimization process.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.5
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• pp.892-901
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• 2001

Despite of many advantages over conventional radio paths, application of the Meteor Burst Path in commercial communication system is so far limited to a few extent because of its low duty rate, which is, less than several percent at best. In order to get through maximum number of data bits during the short interval of each burst, which normally lives a fractions of a second, a sophisticated communication protocol is called for. In this paper, author introduces a communication protocol which can effectively locate and fetch burst signal by sending out periodic detection signal from master station and, with minimal delay, switch over to transmission states so as to put as many data bits through the detected burst as the burst length permits. By analyzing time period required for each transaction steps, the author derives optimal packet length for various bursts which assures to get a message string through in minimum delay. According to the analysis, the author proposes a protocol including a routine which automatically accesses average length of bursts at each environment and automatically adapt length of data packet so as to maximize data throughput under Riven burst conditions.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.4
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• pp.157-164
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• 2023

This paper suggests O(n²) polynomial time heuristic algorithm for corporate tax structure optimization problem that has been classified as NP-complete problem. The proposed algorithm constructs tax tree levels that the target holding company is located at root node of Level 1, and the tax code categories(T_e) 1,4,3,2 are located in each level 2,3,4,5 sequentially. To find the maximum tax-relief path from source(S) to target(T), firstly we connect the minimum witholding tax rate _minr_w(u, v) arc of node u point of view for transfer the profit from u to v node. As a result we construct the spanning tree from all of the source nodes to a target node, and find the initial feasible solution. Nextly, we find the alternate path with minimum foreign tax rate _minr_fi(u, v) of v point of view. Finally we choose the minimum tax-relief path from of this two paths. The proposed heuristic algorithm performs better optimal results than linear programming and Tabu search method that is a kind of metaheuristic method.

• Journal of the Korea Society of Computer and Information
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• v.12 no.4
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• pp.43-52
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• 2007

As the number of public Web Services increases, there will be many services with the same functionality. These services. however, will vary in their QoS properties, such as price, response time and availability, and it is very important to choose a best service while satisfying given QoS constraints. This paper brings parallel branching and response time constraint of business processes into focus and investigates several service selection plans based on multidimensional multiple choice Knapsack model. Specifically. proposed in the paper are a plan with response time constraints for each execution flow, a plan with a single constraint over the whole service types and a plan with a constraint on a particular execution path of a composite Web Services. Experiments are conducted to observe the performance of each plan with varying the number of services, the number of branches and the values of response time constraint. Experimental results show that reducing the number of candidate services using Pareto Dominance is very effective and the plan with a constraint over the whole service types is efficient in time and solution quality for small to medium size problems.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.6
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• pp.33-39
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• 2023

Recently, reinforcement learning has been used to improve the communication performance of flying ad-hoc networks (FANETs) and to design mobility models. Mobility model is a key factor for predicting and controlling the movement of unmmaned aerial vehicle (UAVs). In this paper, we designed and analyzed the performance of Q-learning with fourier basis function approximation and Deep-Q Network (DQN) models for optimal path finding in a three-dimensional virtual environment where UAVs operate. The experimental results show that the DQN model is more suitable for optimal path finding than the Q-learning model in a three-dimensional virtual environment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.473-476
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• 2008

USN(Ubiquotous Sensor Network) has been applied to various fields of industries such as logistics, environment management, traffic management, as well as IT industries including home network and telematics. Among the important techniques required to implement aforementioned applications, location management scheme is essential. In this paper, we proposed and implemented a new location measurement scheme based on RSSI of sensor node for campus car location management.

• Journal of Convergence Society for SMB
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• v.4 no.1
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• pp.7-15
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• 2014

In this paper, we propose an efficient routing protocol to achieve an optimal route searching process of the network lifetime by balancing power consumption per node. The proposed protocols aim at finding energy-efficient paths at low protocol power. In our protocol, each intermediate node keeps power level and branch number of child nodes and it transmits the data the nearest neighbor node. Our protocol may minimize the energy consumption at each node, thus prolong the lifetime of the system regardless of the location of the sink outside or inside the cluster. In the proposed protocol for inter-cluster communication, a cluster head chooses a relay node from its adjacent cluster heads according to the node's residual energy and its distance to the base station. Simulation results show that proposed protocol successfully balances the energy consumption over the network, and achieves a remarkable network lifetime improvement as highly as 7.5%.