• Environmental and Resource Economics Review
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• v.12 no.2
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• pp.299-325
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• 2003

This study uses Conrad's model(nominal fishing effort) of a fishery to analyze theoretically the effects of cost changes on fishing effort, harvest level, and stock size. Static and dynamic open access effects are also modeled present value maximizing scenarios through simulations, and compared an extended model, Cunningham's model(diminishing fishing effort). Results show that an increase in the unit cost of effort goes up the fish stock in static open access, but open access dynamics shows the exhaustion of fish stock as the unit cost of effort decreases. In conclusion, we can derive the optimal equilibrium of resource, given conditions and parameters, as well as utilize this comparative statics to efficient fishery management.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2837-2843
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• 2015

This study firstly finds the factors for positive development of urban regeneration cases from the point of view of a public sector, and then analyzes the development potential of Urban Regeneration Projects in Gyeonggi-do through the methodology able to measure the development potential objectively. The process to analyze the development potential is as follows. First, after finding indices through literature review, indices with redundancy and similarity are drawn by the discussion with relative experts. Second, four clusters and twelve indices are drawn by the verification of experts. Finally, criticality analysis of indices are analyzed by ANP. According to the result to apply criticality analysis of indices to urban regeneration cases, factors related to residential environment and local economy influence development potential more than those related to infrastructures and land-use.

• Journal of Korea Game Society
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• v.17 no.6
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• pp.19-28
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• 2017

There exist a variety of VR(Virtual Reality) contents that have been developed by the use of the latest VR technologies. Unlike the rapid advances in the recent VR devices however, the development of VR based game contents that fully utilize such cutting-edge devices has been lackluster. Using more accessible form of smartphone-based HMDs(Head-Mounted Displays), we compare two popular VR presentation methods(a realistic 3D VR karaoke room and a 360 degree video karaoke room) and analyze their users' immersion and realistic perception. We expect that our study can be utilized as a supporting guideline for future smartphone-based VR content developments.

• Journal of the Korea Society of Computer and Information
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• v.15 no.2
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• pp.155-162
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• 2010

To ensure accurate measurements of wireless network performance, it should be collected real-time data which are transmitted between a large number of nodes in the actual network environment. Therefore, it is necessary to develop simulation tool for finding optimal network system design method such as media access control, routing technique, ad-hoc algorithm of node deployment while overcoming spatial and temporal constraints. Our research attempts to provide an improved architecture and design method of simulation tool for wireless network is an application of multi-threading technique in these issues. We finally show that usability of the proposed simulator by comparing results derived from same test environment in the wireless LAN model of our simulator and widely used network simulation package, NS-2.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.5
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• pp.1356-1364
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• 1990

This paper deals with the preliminary design conditions of Stirling Engines based on an adiabatic analysis with regenerator effectiveness. The investigation of thermal regeneration process results that the definition of effectiveness proposed by Urieli et al. is appropriate for the present model. Then, it is applied to the already existing approximate analytic solution for the adiabatic model in order to optimize thermal efficiency as well as work parameter. Results show that thermal efficiency is less sensitive to the variation in design parameters than work. Phase angle for the maximum work is also the most efficient at high values of the effectiveness. Swept volume ratio should be chosen with care. The optimum value of dead volume ratio is at least less than the maximum efficiency condition. The feasible design range in compression ratio lies between the maximum efficiency condition and the structural limit of Stilring Engines, where the higher its value, the better. Changes in the temperature ratio do not alter the design conditions. Working fluids with the specific heat ratio 1.67 are more efficient that those with 1.4.

• The Journal of Society for e-Business Studies
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• v.12 no.2
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• pp.31-45
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• 2007

Over the past decades, there have been numerous studies for approaches to build and operate electronic government systems. Among those studies, work breakdown structure(WBS) has been gained attention increasingly. As a general system engineering techniques. WBS is a kind of methods to engineer and manage electronic government systems effectively. WBS is to organizes tasks and data items for management and engineering for electronic government systems. In this paper, the authors proposed a conceptual WBS model for management and engineering electronic government systems. Also, the authors conducted a case study based on the conceptual WBS model. The results of this study provide useful insights and guidelines for applying the WBS to management and engineering for electronic government systems. The authors believed that the conceptual WBS models will be widely used to management and engineering an electronic government systems.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.1037-1040
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• 2008

In order to predict the remaining life of marine concrete structures under climatic loads, it is necessary to develop an analytical approach to predict the time and space dependent deterioration of concrete structures due to mainly chloride attack up to corrosion initiation and additional deterioration like cracking of cover concrete. This study aims to introduce FEM model for life-time simulation of concrete structures subjected to chloride attack. In order to consider uncertainties in materials as well as environmental parameters for the prediction, Monte Carlo Simulation is integrated in that FEM modeling for reliability-based remaining service life prediction. The paper is organized as follows: firstly general scheme for reliability-based remaining service life of concrete structures is introduced, then the FEM models for chloride penetration, corrosion product expansion and cover cracking are briefly explained, finally an example is demonstrated and the effects of localization of chloride concentration and corrosion product expansion on service life using above model are discussed.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.1053-1056
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• 2008

Permeability coefficient of concrete is a substantial key parameter for understanding the durability performance of concrete and its micro-structural densification. Many researches to deal with the issue have been accomplished, however, it is very rare to deal with the theoretical study on permeability coefficient in connection with carbonation of concrete and the effect of volumetric fraction of cement paste or aggregate on the permeability coefficient. The majority of these researches have not dealt with this issue combined with carbonation of concrete, although carbonation can significantly impact on the permeability coefficient of concrete. The purpose of this study is to establish a fundamental approach to compute the permeability coefficient of (non)carbonated concrete. When simulating micro-structural characteristics as a starting point for deriving a model for the permeability coefficient by the numerical simulation program for cementitious materials, HYMOSTRUC, a more realistic formulation can be achieved. For several compositions of cement pastes, the permeability coefficient is calculated with the analytical formulation, followed by a microstructure-based model. Emphasis is on the micro-structural changes and its effective change of the permeability coefficient of carbonated concrete. The results of micro-structural water permeability coefficient model will be compared with results achieved from permeability experiments.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.6
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• pp.483-490
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• 2015

There are many software reliability models that are based on the times of occurrences of errors in the debugging of software. It is shown that it is possible to do likelihood inference for software reliability models based on finite failure model and non-homogeneous Poisson Processes (NHPP). For someone making a decision about when to market software, the conditional failure rate is an important variables. The infinite failure model are used in a wide variety of practical situations. Their use in characterization problems, detection of outlier, linear estimation, study of system reliability, life-testing, survival analysis, data compression and many other fields can be seen from the many study. Statistical process control (SPC) can monitor the forecasting of software failure and thereby contribute significantly to the improvement of software reliability. Control charts are widely used for software process control in the software industry. In this paper, proposed a control mechanism based on NHPP using mean value function of Musa-Okumo and Power law type property.

• The KIPS Transactions:PartB
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• v.14B no.3 s.113
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• pp.199-214
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• 2007

Recently, there have been a lot of works trying to realize automated composition of semantic web services though application of AI planning techniques. The traditional AI planning techniques, however, have some limitations: it is not easy to represent a web service process with complex control constructs as an action or a plan; it is hardly possible to consider enough the rich information contained in domain ontologies during the planning process; it is impossible to model directly the data flow from the outputs of a web service to the inputs of another web service; it is difficult to predict and deal with uncertainty and dynamics of the environment because the plan generation phase is supposed to be separated from the plan execution phase. In order to overcome some of these limitations, this paper suggests a reactive planning approach to automated composition of semantic web services. Through some experiments using several e-commerce web services, we found that the reactive planning is an effective way to realize automated composition of semantic web services.